1. Field of the Invention
The present invention relates to an etching method, etching system, and etching apparatus for etching a silicon oxide film formed on a substrate to form a hole, such as a storage node hole or contact hole, which reaches a contact portion.
2. Description of the Related Art
In recent years, along with an increase in integration of semiconductor devices, miniaturization of pattern sizes has been making remarkable progress. For example, in the process of manufacturing DRAMs, capacitor electrodes having a cylindrical shape need to be thinner while they need to be higher to increase the capacitance. Further, the storage node holes need to have a higher aspect ratio. The contact holes also need to have a higher aspect ratio.
Jpn. Pat. Appln. KOKAI Publications No. 2002-313952 discloses a technique for forming a storage node hole or contact hole having a high aspect ratio and a good shape.
However, where such a deep hole is formed, the hole becomes thinner before it reaches the contact portion. This may bring about a difficulty in making sufficient contact between the contact material inside the hole and the contact portion. Further, where the hole has a small diameter, it may be difficult to make sufficient contact, even where the hole has a good shape.